Jeffery Machat, MD, Medical Director, TLC Toronto
There is currently a debate in the refractive community as to whether or not Wavefront Optimized LASIK creates the same visual performance as Wavefront Guided. Now more than ever, patients have greater expectations from their refractive surgeons. As such, surgeons want to be able to offer the best visual results in the most reliable manner. Surgeons therefore need the best information that is available in order to choose the most effective ablation pattern to achieve emmetropia. At our facility in Canada we have had the WaveLight, Allegretto and the VISX laser, all for over five years. Originally when we began using the WaveLight laser, we only had the VISX S3, then we upgraded to the S4 with CustomVue which was a dramatic improvement Over a year ago we began using iris registration with even more impressive results.
It is rare that a week does not go by without a surgeon asking me to compare the two lasers. Compared to the VISX S3 and the SmoothScan program, the WaveLight was my laser of choice. However, today, the dramatically better results with the VISX S4 with CustomVue and IR makes the debate very one-sided in favor of the VISX laser.
Personal Experience
I began using the WaveLight in 2001 and utilized it in about 1,500 successful cases my first year. At that point we had 4 excimer lasers and I was comparing it to the VISX S3 with SmoothScan, the Bausch and Lomb Technolas 217Z and the Alcon LadarVision 2000. My first experience with wavefront began on March 6, 2000, with Zyoptix® on my Technolas® laser, which was disappointing and did not meet my expectations or that of my patients.
At that time, night glare and low light visual quality were of primary concern with my patients as well as within the refractive community, and wavefront had seemed to be the answer. Standard ablation patterns treated only defocus and astigmatism, which are considered second or lower order aberrations, and only account for about 75% of the aberrations in the eye. Simply put, the other 25% of aberrations are considered higher order aberrations, “essentially those aberrations not corrected with glasses,” chiefly coma and spherical aberration. More importantly, refractive surgery induces higher order aberrations and it was the induction of spherical aberration that created the night glare issues for our patients. So the idea of having an aspheric profile, which is what the WaveLight excimer laser system produced, to deal with the problems of spherical aberration was very appealing. The simplicity of the system also made it very attractive for my practice, eliminating the wavefront analyzer, keycards and improving my patient flow and procedure speed. In direct contrast to the Ladar platform, the WaveLight had excellent ergonomics, a high repetition rate with a small spot size and the eye tracker did not require dilatation. We were impressed with the clinical results and definitely noted better night vision with fewer complaints from the majority of our patients compared to other platforms.
However, when VISX introduced the S4 with CustomVue the comparison suddenly began shifting in favor of the VISX . The clinical results were definitely better, we had greater gains in best-corrected vision; we had happier referring doctors, and more referrals from our patients. Our retreatment rate was also substantially lower with VISX CustomVue compared to the WaveLight. We began charging a premium price several hundred dollars more for VISX CustomVue as well. Gradually over the next year, we had shifted from 70% WaveLight to 90% VISX CustomVue. Our referring doctors instigated the shift, and our staff endorsed it wholeheartedly as they had fewer and fewer enhancements and complaints to deal with. The WaveLight basically put a standard spherical equivalent coefficient into every single treatment, simply adding additional pulses in the periphery to compensate for the induced spherical aberration. The Wavefront optimized approach did not adjust the number of pulses based upon the amount of spherical aberration present pre-operatively, nor did it treat coma, trefoil or any other asymmetrical higher order aberrations of clinical significance. Furthermore patients with negative spherical aberration were worsened by the Wavefront Optimized ablation (WFO) pattern and these patients along with those with significant or induced coma became a growing source of retreatments and complaints for my staff and I to manage. Lastly, we had no way to effectively retreat these unhappy WaveLight patients other than to utilize VISX CustomVue. While we still today have our WaveLight laser it has been over a year since my partners and I have used the laser and I suspect that it will find another home where it is wanted. Today, we are 100% VISX CustomVue with IR combined with IntraLase for corneal flap creation, and night vision complaints are virtually non-existent.
The Case Study that drove our transition to 100% VISX CustomVue
Perhaps the most compelling case that solidified our 100% transition to CustomVue arose from a 35-year-old man who was treated with the WaveLight WFO program by my colleague. The patient pre-operatively was -2.75D OU, essentially spherical with completely normal clinical findings, 550 micron pachymetry, 6 mm pupils, and normal topographies, who clearly seemed to be an ideal LASIK candidate. My partner performed a very uneventful LASIK procedure on both eyes with our WaveLight , which resulted in the patient achieving emmetropia and seeing 20/20 post operatively from Day 1. Of course he assumed that the patient would be thrilled.
On the contrary, the patient was very unhappy with his vision, complaining about the poor visual quality, returning several times a month and calling even more frequently, about his inability to function at work and even perform his normal activities of daily living. The patient truly felt completely debilitated. My colleague asked me to examine the patient and determine if I felt the complaints were genuine, and make any suggestion I thought would be helpful. The only clinical finding was an increase in his coma post-operatively from .17 to .39 in his worst eye.
Obviously, the patient wanted an enhancement, but common sense warned my partner not to do anything, and certainly operating on a person who is seeing at 20/20 and has a cycloplegic refraction of plano OU would carry medicolegal risk. Any further treatment my partner correctly felt would likely only result in trouble for the both the patient and surgeon and carried a high risk of inducing hyperopia. Nevertheless, the complaints went on for months resulting in my partner finally relenting and agreeing to retreat this patient, a decision that I supported. There was simply no way by which to enhance this patient, nor our other small percentage of unhappy WaveLight patients without VISX CustomVue.
My partner retreated the patient with straight WaveScan numbers one eye at a time, a month apart, with five seconds of treatment on the left eye, six seconds on the right eye. Day one post-op the patient remained 20/20 plano after each retreatment and the vision quality of the patient was dramatically improved which the patient described as “ lifting the film of blur away” and “everything is brighter”.
My partner was surprised at how such a small amount of coma could debilitate a patient so severely, and such a small CustomVue treatment could create such a dramatic improvement. He assumed that since the patient had a low refractive error with low higher order aberrations pre-operatively, that he would be suitable for a Wavefront Optimized procedure and did not require a Wavefront Guided procedure; but that is a false belief that many refractive surgeons carry, as it is those patients that are most sensitive to increases in their higher order aberrations. This was simply one of those clinical cases that can open your eyes to an issue and forever change your thinking. My partners and I rapidly transitioned to 100% VISX CustomVue and we are forever pleased with that decision. Our patients seem to concur.